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Tesche M.,University of Hertfordshire | Glantz P.,University of Stockholm | Johansson C.,University of Stockholm | Johansson C.,Environment and Health Administration
Tellus, Series B: Chemical and Physical Meteorology | Year: 2016

This article investigates the feasibility of using spaceborne observations of aerosol optical thickness (AOT) derived with the Moderate Resolution Imaging Spectroradiometer (MODIS) for monitoring of fine particulate matter (PM2.5) in an environment of low aerosol loading. Previous studies of the AOT-to-PM2.5 relationship benefit from the large range of observed values. The Stockholm region features a comprehensive network of ground-based monitoring stations that generally show PM2.5 values < 20 mg m-3. MODIS AOT at 555nm is usually B0.20 and in good agreement with ground-based sun photometer observations in this region. We use MODIS Collection 5 AOT data with a horizontal resolution of 10km×10km and ground-based in-situ PM2.5 observations to derive an AOT-to-PM2.5 relationship that can be used to estimate fields of PM2.5. This has been carried out with respect to the months from April to September of the period 2000-2013. Relative average absolute deviations of 33-55 % (mean of 45 %) are obtained between MODIS-retrieved and ground-based PM2.5. The root mean square error is 0.2159 mgm-3 between retrieved and measured PM2.5. From spaceborne lidar observations, it is found that elevated aerosol layers are generally sparse in the Stockholm region. This favours remote sensing of PM2.5 from space. The deviations found between measured and retrieved PM2.5 are mainly attributed to infrequent situations of inhomogeneous aerosol layering for which column-integrated observations cannot be connected to surface conditions. Using MODIS Collection 6 data with a resolution of 3km-3 km in a case study actually gives far fewer results than the coarser Collection 5 product. This is explained by the complex geography of the Stockholm region with a coastline and an abundance of lakes, which seems to induce biases in the retrieval of AOT at higher spatial resolution. © 2016 M. Tesche et al.

Gruzieva O.,Karolinska Institutet | Gruzieva O.,National Oo Bohomolets Medical University | Bellander T.,Karolinska Institutet | Eneroth K.,Environment and Health Administration | And 10 more authors.
Journal of Allergy and Clinical Immunology | Year: 2012

Background: The role of exposure to air pollution in the development of allergic sensitization remains unclear. Objective: We sought to assess the development of sensitization until school age related to longitudinal exposure to air pollution from road traffic. Methods: More than 2500 children in the birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiological Survey) from Stockholm, Sweden, were followed with repeated questionnaires and blood sampling until 8 years of age. Outdoor concentrations of nitrogen oxides, as a marker of exhaust particles, and particles with an aerodynamic diameter of less than 10 μm (PM 10), mainly representing road dust, were assigned to residential, day care, and school addresses by using dispersion models. Time-weighted average exposures were linked to levels of IgE against common inhalant and food allergens at 4 and 8 years of age. Results: Air pollution exposure during the first year of life was associated with an increased risk of pollen sensitization at 4 years of age (odds ratio, 1.83; 95% confidence interval, 1.02-3.28) for a 5th to 95th difference in exposure to nitrogen oxides. At 8 years, there was no general increase in the risk of sensitization; however, the risk of food sensitization was increased, particularly among children free of sensitization at 4 years of age (odds ratio, 2.30; 95% confidence interval, 1.10-4.82). Results were similar by using PM 10. No associations between air pollution exposure after the first year of life and sensitization were seen. Conclusion: Traffic-related air pollution exposure does not seem to increase the overall risk of sensitization to common inhalant and food allergens up to school age, but sensitization to certain allergens might be related to exposure during infancy. © 2011 American Academy of Allergy, Asthma & Immunology.

PubMed | Karolinska Institutet, Center for Occupational and Environmental Medicine, Environment and Health Administration and Karolinska University Hospital
Type: Journal Article | Journal: Journal of exposure science & environmental epidemiology | Year: 2015

We investigated the risk of stroke related to long-term ambient air pollution exposure, in particular the role of various exposure time windows, using four cohorts from Stockholm County, Sweden. In total, 22,587 individuals were recruited from 1992 to 2004 and followed until 2011. Yearly air pollution levels resulting from local road traffic emissions were assessed at participant residences using dispersion models for particulate matter (PM10) and nitrogen oxides (NOX). Cohort-specific hazard ratios were estimated for time-weighted air pollution exposure during different time windows and the incidence of stroke, adjusted for common risk factors, and then meta-analysed. Overall, 868 subjects suffered a non-fatal or fatal stroke during 238,731 person-years of follow-up. An increment of 20g/m(3) in estimated annual mean of road-traffic related NOX exposure at recruitment was associated with a hazard ratio of 1.16 (95% CI 0.83-1.61), with evidence of heterogeneity between the cohorts. For PM10, an increment of 10g/m(3) corresponded to a hazard ratio of 1.14 (95% CI 0.68-1.90). Time-window analyses did not reveal any clear induction-latency pattern. In conclusion, we found suggestive evidence of an association between long-term exposure to NOX and PM10 from local traffic and stroke at comparatively low levels of air pollution.

Sunnerstedt E.,Environment and Health Administration
26th Electric Vehicle Symposium 2012, EVS 2012 | Year: 2012

The City of Stockholm and Vattenfall have together with SKL Kommentus Inkopscental AB carried out a national Swedish procurement resulting in frame work agreements regarding electric vehicles (pure electrical vehicles and plug-in hybrids) from five different suppliers (both passenger cars and light duty van). The contracted suppliers are: Chevrolet, Citroen, Mitsubishi, Renault, Vantage/Avancee. Both public bodies and private companies were invited to join the procurement. A total number of 296partners/buyers have stated an estimated purchase volume of 1 250 electric vehicles/year. The contact period stared on October 1, 2012 and is for two years but may be prolonged for a total time of four years. The Swedish Energy Agency is providing financial support with approximately 5000 €/vehicle for the first 1000 vehicles that are bought through the procurement frame work contracts.

Oudin A.,Umeå University | Carlsen H.K.,University of Iceland | Forsberg B.,University of Stockholm | Johansson C.,Environment and Health Administration
International Journal of Environmental Research and Public Health | Year: 2013

In the aftermath of the Icelandic volcano Grimsvötn's eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24-31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study effects of the Grimsvötn ash on morbidity and mortality. Such studies would be of particular importance for European societies preparing for future large scale volcanic eruptions in Iceland. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Meister K.,Umeå University | Johansson C.,University of Stockholm | Johansson C.,Environment and Health Administration | Forsberg B.,Umeå University
Environmental Health Perspectives | Year: 2012

Background: Although serious health effects associated with particulate matter (PM) with aerodynamic diameter ≤ 10 μm (PM 10) and ≤ 2.5 μm (PM 2.5; fine fraction) are documented in many studies, the effects of coarse PM (PM 2.5-10) are still under debate. Objective: In this study, we estimated the effects of short-term exposure of PM 2.5-10 on daily mortality in Stockholm, Sweden. Method: We collected data on daily mortality for the years 2000 through 2008. Concentrations of PM 10, PM 2.5, ozone, and carbon monoxide were measured simultaneously in central Stockholm. We used additive Poisson regression models to examine the association between daily mortality and PM 2.5-10 on the day of death and the day before. Effect estimates were adjusted for other pollutants (two-pollutant models) during different seasons. Results: We estimated a 1.68% increase [95% confidence interval (CI): 0.20%, 3.15%] in daily mortality per 10-μg/m 3 increase in PM 2.5-10 (single-pollutant model). The association with PM 2.5-10 was stronger for November through May, when road dust is most important (1.69% increase; 95% CI: 0.21%, 3.17%), compared with the rest of the year (1.31% increase; 95% CI: -2.08%, 4.70%), although the difference was not statistically significant. When adjusted for other pollutants, particularly PM 2.5, the effect estimates per 10 μg/m 3 for PM 2.5-10 decreased slightly but were still higher than corresponding effect estimates for PM 2.5. Conclusions: Our analysis shows an increase in daily mortality associated with elevated urban background levels of PM 2.5-10. Regulation of PM 2.5-10 should be considered, along with actions to specifically reduce PM 2.5-10 emissions, especially road dust suspension, in cities.

Sadiktsis I.,University of Stockholm | Bergvall C.,University of Stockholm | Johansson C.,University of Stockholm | Johansson C.,Environment and Health Administration | Westerholm R.,University of Stockholm
Environmental Science and Technology | Year: 2012

Eight tires were analyzed for 15 high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAH), using pressurized fluid extraction. The variability of the PAH concentrations determined between different tires was large; a factor of 22.6 between the lowest and the highest. The relative abundance of the analytes was quite similar regardless of tire. Almost all (92.3%) of the total extractable PAH content was attributed to five PAHs: benzo[ghi]perylene, coronene, indeno[1,2,3-cd]pyrene, benzo[e]pyrene, and benzo[a]pyrene. The difference in the measured PAH content between summer and winter tires varied substantially across manufacturers, making estimates of total vehicle fleet emissions very uncertain. However, when comparing different types of tires from the same manufacturer they had significantly (p = 0.05) different PAH content. Previously, there have been no data available for carcinogenic dibenzopyrene isomers in automobile tires. In this study, the four dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene, and dibenzo[a,h]pyrene constituted <2% of the sum of the 15 analyzed HMW PAHs. These findings show that automobile tires may be a potential previously unknown source of carcinogenic dibenzopyrenes to the environment. © 2012 American Chemical Society.

Andersson A.,University of Stockholm | Sheesley R.J.,University of Stockholm | Krusa M.,University of Stockholm | Johansson C.,University of Stockholm | And 2 more authors.
Atmospheric Environment | Year: 2011

Combustion-derived soot or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In order to propose effective mitigation strategies for BC emissions it is of importance to investigate geographical distributions and seasonal variations of BC emission sources. Here, a radiocarbon methodology is used to distinguish between fossil fuel and biomass burning sources of soot carbon (SC). SC is isolated for subsequent off-line 14C quantification with the chemothermal oxidation method at 375 °C (CTO-375 method), which reflects a recalcitrant portion of the BC continuum known to minimize inadvertent inclusion of any non-pyrogenic organic matter. Monitored wind directions largely excluded impact from the Stockholm metropolitan region at the EMEP-Aspvreten rural station 70 km to the south-west. Nevertheless, the Stockholm city and the rural stations yielded similar relative source contributions with fraction biomass (fbiomass) for fall and winter periods in the range of one-third to half. Large temporal variations in 14C-based source apportionment was noted for both the 6 week fall and the 4 month winter observations. The fbiomass appeared to be related to the SC concentration suggesting that periods of elevated BC levels may be caused by increased wood fuel combustion. These results for the largest metropolitan area in Scandinavia combine with other recent 14C-based studies of combustion-derived aerosol fractions to suggest that biofuel combustion is contributing a large portion of the BC load to the northern European atmosphere. © 2010 Elsevier Ltd.

PubMed | Umeå University and Environment and Health Administration
Type: Journal Article | Journal: BMJ open | Year: 2015

For the past two decades, several studies have reported associations between elevated levels of ambient air pollution and adverse pregnancy outcomes, although with varying conclusions.To examine possible associations between the traffic pollution situation at the home address, for women who did not change address during pregnancy, and three types of pregnancy outcomes: spontaneous preterm delivery, children born small for gestational age (SGA) and pregnancy-induced hypertensive disorders.We used data for the Greater Stockholm Area from the Swedish Medical Birth Register to construct a cohort based on all pregnancies conceived between July 1997 and March 2006, n = 100 190. The pregnancy average nitrogen oxide, NOx, levels and annual mean daily vehicles at the home address were used as exposure variables. Mixed-model logistic regression was performed to assess any associations between exposure and outcome.There was an association between elevated traffic pollution exposure during pregnancy and pregnancy-induced hypertensive disorders. A 10 g/m(3) increase in the pregnancy average NOx level at the home address resulted in an OR of 1.17 (95% CI 1.10 to 1.26). The 2nd to 4th quartiles of NOx were all associated with an increased risk of SGA, but there was no difference in the risk estimate among the higher quartiles. There was a tendency of a higher risk of spontaneous preterm delivery in relation to higher levels of NOx. There was no evidence of an association between vehicle flow, the cruder indicator of traffic pollution, and the studied outcomes in this study.In this large cohort, there was a fairly strong association between vehicle exhaust levels at the home address and pregnancy-induced hypertensive disorders, after adjustment for important risk factors.

PubMed | The Swedish School of Sport and Health Sciences, WSP Civils, Umeå University, University of Stockholm and Environment and Health Administration
Type: | Journal: The Science of the total environment | Year: 2017

Our study is based on individual data on peoples home and work addresses, as well as their age, sex and physical capacity, in order to establish realistic bicycle-travel distances. A transport model is used to single out data on commuting preferences in the County Stockholm. Our analysis shows there is a very large potential for reducing emissions and exposure if all car drivers living within a distance corresponding to a maximum of a 30min bicycle ride to work would change to commuting by bicycle. It would result in >111,000 new cyclists, corresponding to an increase of 209% compared to the current situation. Mean population exposure would be reduced by about 7% for both NO

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